Automatic optical control apparatus



Nov. 28, 1967 G. P, TAlLLlE ET AL 3,355,236

AUTOMATIC OPTICAL CONTROL APPARATUS Filed Jan. 1964 13 sheetsfsheet 2 INVENTOR. GORDON P. TAILLIE RALPH R. TILLY N i5 ll.

Nov. 28, 1967 G. P. TAILLIE ET AL 3,355,236

AUTOMATIC OPTICAL CONTROL APPARATUS 13 Sheets-Sheet :5

Filed Jan. :1, 1964 A T TOR/VE Y Nov. 28, 1967 G. P. TAILLIE- ET AL 3,355,236

AUTOMATIC OPTICAL CONTROL APPARATUS 13 Sheets-Sheet 4 Filed Jan. it, 1964 ATTORNEY 13 Sheets-Sheet 6 G. P. TAILLIE ET AL Mor# INVENTOR. GORDON P. TAILVE RALPH R. TILL.

TTORNEY AUTOMATIC OPTICAL CONTROL APPARATUS Nov. 28, 1967 Filed Jrm. f.. 1964 FIG. 8

Nov. 28, 1967 G. P. TAILLIE ET AL 3,355,236

AUTOMATIC OPTICAL CONTROL APPARATUS A7' TOR/VE Y Nov. 28, 1967 G. P. TAILLIE ET AL AUTOMATIC OPTICAL CONTROL APPARATUS 13 Sheets-Sheet 8 Filed Jan. riz. 1964 MOT- 7 m E RLY OIL TAL 0 mrn r vP. m R. WH DP w RL OA GR FIG. 1I

Nov. 28, 1967 G. P. TAILLIE ET AL 3,355,236

AUTOMATIC OPTICAL CGNTROL APPARATUS 13 Sheets-Sheet ifilm Jan. t, 1064 0f INVENTR. GORDON P. TAILLIE RALPH R. ILLY B ATTORNEY Nov. 28, 1967 Q p TA|LL|E ET Al. 3,355,236

AUTOMATIC Of'TlCAL CONTHH. AI'I'AHA'IIIS Filed Jan. 22, 1964 13 SNMP-Sheet, lO

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A TTORNE Y 13 Sheets-Sheet 11 G. P. TAILLIE ETAL AUTOMATIC OPTICAL CONTROL APPARATUS Nov. 28, |967 Filed Jan. 1964 TAILLIE TILLY 315/ INVENTOR.

TTORNEY GORDON P. RALPH R. B

United States Patent O 3,355,236 AUTOMATIC OPTICAL CONTROL APPARATUS Gordon Philip Taillie, Rochester, and Ralph R. Tilly,

Ontario, N.Y., assignors to Xerox Corporation, Rochester, N.Y.. a corporation of New York Filed Jan. 2, 1964, Ser. No. 335,242 2 Claims. (Cl. 350-187) ABSTRACT OF THE DISCLOSURE Apparatus for electrically controlling the length of the light path and the lens position in an optical system so that enlarged or reduced copies of an original can be produced in an apparatus having a fixed image and object plane.

This invention relates to an optical system for use in document reproducing apparatus and, in particular, to an improved optical system which permits an automatic enlargement or reduction of theI document being reproduced.

More specifically, the invention relates to an improved optical system containing mirrors and lens assemblies which are automatically positionable relative to a document conveyor and to a Xerographic processor, for transmittal of a light image from a scanning station in the document conveyor to the Xerographic processor. The process of Xerography, and apparatus capable of producing xerographic copies from a light image, is fully disclosed in Hunt et al. Patent No. 3,078,770, issued Feb. 26, 1963.

Although there are a variety of Xerographic or electrostatic reproducing machines commercially available, they all either reproduce from microfilm or make copies from documents without enlargement or reduction other than that normally encountered in an actual size reproduction. The machines commercially available are not capable of permitting the operator to select an enlargement or reduction, nor are they capable of reproducing large documents, such as engineering drawings. They are primarily restricted to letter size or legal size documents.

In order to make reproducing machines adaptable to various size documents and in order to produce various enlargements or reductions of the document within a fixed size xerographic processor, it is necessary that the optical system be adjustable to change the length of the light path of the optical image and the relative position of the lens and mirrors within the optical system.

It is, therefore, the primary object of this invention to improve optical systems used in xerographic reproducing apparatus for copying large documents.

Another object of this invention is to improve optical systems used in xerographic reproducing apparatus so that enlargements or reductions of light images of documents being reproduced may be accomplished automatically.

It is a further object of this invention to improve optical systems to permit changes in the optical characteristics of the system without removing the lens or mirrors in the system.

It is a further object of this invention to improve optical systems used in Xerographic reproducing apparatus so that enlargements or reductions of a light image being transmitted through the optical system may be varied merely by changing the relative location of the individual elements of the system.

It is also an object of this invention to fully automate the optical system of a Xerographic reproducing apparatus.

These and other objects of the invention are attained by means of a unitary optical system which is movable relative to a document being reproduced and to a xerographic processor to which a light image of the document being reproduced is to be transmitted, a lens system within the optical system which is movable relative to the other elements of the optical system, and the necessary controls to regulate the position of the optical assembly and the lens assembly for a preselected image size.

For a better understanding of the invention, as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a right-hand perspective view of the Xerographic apparatus of the invention enclosed in a cabinet;

FIG. 2 is a front view of the apparatus with the cabinet covers broken away to show the internal structure of the machine;

FIG. 3 is a left-hand perspective view of the conveyor system used in the apparatus shown in FIG. l;

FIG. 4 is a perspective view of the optical system of the apparatus shown in FIG. 1;

FIG. 5 is a front view, partially sectioned, of the lens drive clutch;

FIG. 6 is a sectional view of the lens drive clutch shown taken along lines 6-6 of FIG. 5;

FIG. 7 is a schematic view of the xerographic apparatus used in the machine shown in FIG. 1;

FIG. 8 is a sectional view taken along lines 8--8 of FIG. 2;

FIG. 9 is an enlarged view of the lens and lens drive mechanism with portions broken away;

FIG. 10 is an enlarged top viewof the lens guiding mechanism taken along lines 10-10 of FIG. 9;

FIG. 11 is a sectional view of the apparatus taken along lines 11-11 of FIG. 2;

FIG. 12 is an enlarged side view of the conveyor discharge station;

FIG. 13 is a sectional view of the Xerographic conveyor drive assembly taken along lines 13-13 of FIG. 7;

FIG. 14 is a sectional view of the mirror drive transmission taken along lines 14-14 of FIG. 8;

FIG. 15 is a side view of the mirror drive transmission with the external covers broken away to show the internal gearing of the mechanism;

FIG. 16 is a rear view of the mirror drive transmission; and

FIGS. 17 and 18 are schematic electrical wiring diagrams of the apparatus.

A Xerographic reproducing apparatus 2 with the cover panels in place is shown in FIG. 1. A document feed-in station is shown at 4 and a front document return bin is shown at 5. There is a copy sheet feed station at 6 and a copy discharge bin at 7. There is a central'panel 8, the details of which are described below and a cover 9 which may be closed t0 partially cover part of the central panel.

FIG. 2 shows a front view of the machine with the covers broken away to show the internal structure of the Xerographic apparatus 10, the document conveying apparatus 12, and the optic system 14.

Document conveyor The document conveyor 12 is seen in FIGS. 2, 3, and 11. An original document of either transparent or opaque material is fed into the conveyor system at feed-in station 4 and is carried on conveyor belts 18 past scanning station 20 to a discharge point 22.

The conveyor belts I8 consist of a series of continuous belts driven by a drive roll 24 around a series of idler rolls 26 and a tensioning roll 28. Mounted above and in contact with the individual strands of conveyor belt 18 are a series of pressure rollers consisting of polyurethane discs 30 mounted in a staggered arrangement on a series of shafts 32. The polyurethane discs hold the document down on the conveyor belts 18 for movement through the conveyor system. A document fed into the conveyor at feed-in station 4 is gripped bctw en the belts 18 and the first two sets of polyurethane discs and moved forward across a platen 34 at exposure station 20. A document, after passing over platen 34, is again picked up by conveyor belts 18 and the polyurethane discs 30 and transported to the discharge station 22. The platen 34 has a reflective or flat white surface to reflect light that has passed through a document back through the document to reinforce the light image reilected from the document surface.

Two conveyor frame members 35 and 36 provide support for the shafts 38 supporting thc idler rollers 26, shaft 40 supporting the drive roll 24, and shaft 42 supporting the tensioning roller 28. The shafts 38 and 40 are mounted in bearing assemblies 44 inside frame members 35 and 36. The shaft 42 supporting the tensioning roller Z8 is mounted in a slotted adjustment block 46 mounted on the side frame members. A bolt 48 passes through the block 46 and the shaft 42 and serves to position the shaft to adjust the tension on the belts 18.

Mounted on the front of the side frame members 35 and 36 are a pair of brackets 50 supporting a pair of misfeed switches SLS and 6LS. Actuating arms 52 extend upward from the switches and, as described below, serve to stop the conveyor if a document is misfed in such a manner as to contact either actuating arm 52, thus insuring proper alignment of a document fed into the conveyor system. A plate 4 extends across and under the conveyor belts 18 and has a series of finger-like extensions 56 which extend between the individual strands of the conveyor belt onto the platen 34. The finger-like extensions 56 are below the upper surface of the belts 18 sothat a document inserted in the machine is picked up by the conveyor 18 and then is carried forward on the linger-like extensions onto the surface of the platen 34. Basically, the finger-like extensions 56 insure that the document does not follow the conveyor system beneath the surface of the platen, but, rather, guide the document up onto the surface of the platen. Mounted above the conveyor belts, on brackets 58, is a document guide 60. The document guide 60 contains linger-like members 62 which extend between the polyurethane rollers 30 onto the surface of the platen 34; thus, as the document passes between the conveyor belts 18 and the polyurethane rollers 30, it is then guided between the linger-like members 56 on the plate 54 and the finger-like members 62 on the document guide 60.

The shafts 32 which support the polyurethane rollers 30 are mounted in bearings 70 in brackets 72. The brackets 72 are mounted on the side frame members 34 and 36 contain a series of fasteners 74 which hold the shafts 32 in position in the brackets 72.

At the rear of the conveyor at discharge station 22, there is a manually operable document dellector 75 which permits a document to be discharged from the conveyor either to the front of the machine or straight out the back of the machine. As seen in FIG. 3, when the dellectcr 75 is down, a document will be deflected from the front surface of the deilector downward between the rol'er 24 and a guide plate 76 so that it is discharged into the document tray 77 in return bin 5 at the front of the machine. If the document being reproduced is of heavy, nonllexible material which will not readily bend around the roller 24 for discharge in the front of the machine, then the document dellector 75 is elevated, as shown in FIG. 12, so that the document may proceed directly out the rear of the machine on platform 78. A resilient member 79, containing ngerlike extensions which extend between the belt strands, prevents the document from following the belts 18 around the roller 24. When the dellector 75 is in a closed position, the resilient member "/'9 is held down against the roller 24.

The deector 75 is mounted on a pair of brackets 80 secured to the side plates 35 and 36 and contains counterff' 4 weights 8L to facilitate movement of the dellector from a closed to an open position. Actuation of the dellector 75 is accomplished through a wedge 82 which, when moved toward the rear of the conveyor, forces a tab 33 on the deflector 7S to rotate the dellector to an open position. The wedge shaped cam 82 is actuated through a linkage consisting of an arm 84 actuated by a pivot block 85 secured to a shaft 86. The shaft 86 is secured in the side plate 35 and is rotated by movement of an arm 87 attached to a linkage member 8S which extends to the front of the machine to be manually actuated by an opcrator. Pushing the linkage 88 toward the rear of the machine forces the Wedge shaped cam 82 back against the document dellector 75, raising the deflector and permitting the document to pass outward through the rear :f the machine. Moving the linkage member 88 toward he front ot' the machine pulls the wedge shaped cam 82 awa; from the dellector 75 permitting the dellector to fall to a position wherein it will deflect the document downward against the guide plate 76 so that it will be accessible in the document bin 5 in the front of the machine.

As best seen in FIGS. 3 and ll, there are a pair of iluoresc tt lights LMP-1 and LMP-2 mounted directly above the platen 34 and encased in a housing 92. In the bottom of the housing 92, directly beneath the fluorescent lights LMP-1 and LMP-2, is a glass plate 94 and, in the middle top of the housing 92, there is a light tunnel 95. The two fluorescent lights are spaced apart so that as a document passes over the platen 34, light is rellected down through the glass plate 94 onto the surface of the document and reflected from the document or from the retlective surface of the platen 34 upward through the glass plate 94 through the light tunnel 96 to the optic system of the apparatus. Two additional lights, LMP-3 and LMP-4, are mounted on the sides of the conveyor and act as lill-in lamps to illuminate the edges of large documents. The lamps are encased in housings 95, as seen in FIG. 2.

Optical system The image reflected from the document surface passes through an optical system, shown in FLG. 4, to the xerographic side of the apparatus. The optic system consists of two front surface mirrors 98 and 102, and a positionable lens 104. The mirror 98 is an object mirror and is positioned above the scanning station at an angle to receive a light image from the scanning station through the optical system, and the mirror 102 is an image mirror positioned above the xerographic processor at an angle to receive a light image from the object mirror and the lens 104 for transmittal to the xerographic processor. Both mirrors are adjustable for alignment in the optical system and are mounted to be secured in position once properly aligned.

The optical system is mounted in a frame or casting 106, which in turn is supported by a threaded nut or sleeve 10S mounted on lead screw 110. The entire frame 106, including the mirrors and lens, may be moved in a vertical direction by rotating the lead screw 110. The entire optical frame is also supported by a column or mast 112 secured to the main frame of the machine and secured to the top of lead screw by plate 114 containing bearing assembly 116. The mast 112 supports and guides the lead screw 110 by means of a frame member 118 welded to the mast at 120 and plate 12,2 containing thrust bearing assembly 124.

The lead screw 110 extends through the thrust bearing 124 into a universal joint 132, as seen in FIG. 8. A linkage member 134 extends between the universal joint 132 and a second universal joint 136. The second universal joint 136 is connected to a shaft 138 from a gear box 140 on the mirror drive transmission 142. The mirror drive transmission is discussed in detail below.

Mounted on the frame 106 between the mirrors 98 and 102 is a movable lens assembly 144. A pair of support brackets 146 and 147 are fastened to the frame 106 and journaled to support a guide shaft 148 and a lead screw 150. The lens assembly 144 is mounted on the guide shaft and the lead screw between the brackets 146 and 147. The lens assembly 144 consists of a lens mounting plate and light shield 152, a casting 153 containing a bearing 154 on the shaft 148, an apertured plate 155, a web 157, and a ange 159. The bearing 154 is movable along the shaft 148 to position the lens assembly at any point between the two brackets 146 and 147. The lens assembly 144 is also guided by means of guide bar 156 and guide rollers 158. As seen in FIGS. 9 and 10, one of the rollers 158 is mounted on the flange 159 of the casting 153, and is rotatably mounted in pressing contact with the guide bar 156. The second roller 158 is rotatably mounted on a pivot bar 162` which forms a yoke and is pivoted about pin 164 passing through an arm 166 rigidly secured to the ange 159. The pivot bar 162 is urged toward the guide bar 156 about the pin 164 by spring 168. The spring 168 is fastened at one end to the pivot bar 162 and at the opposite end to the flange 159, thus urging the roller 158 into contact with the guide bar 156 and providing lateral support for the lens assembly 144 as it moves along shaft 148.

On the back of the apertured plate 155 of the casting 153 there are a pair of lugs 170 to which the lens mounting plate and light shield 152 is secured by means of socket screws 172 and washers 174. The light shield 152 extends upward above the lens assembly 144, as illustrated in FIG. 4, to shield extraneous light from the mirror 102. The plate S on the casting 153 has an aperture 176 through which the lens barrel 178 extends. The lens barrel 178 is attached to the mounting plate and light shield 152 and is optically aligned so that lens 104 receives light from mirror 98 for passage to mirror 102. The lens 104 is held in the lens barrel 178 by retaining ring 180.

The lens assembly 144 is moved along shaft 148 by means of a threaded block 182 fastened to a projecting cam 184 on the bottom of the casting 153. The lens lead screw 150 passes through the threaded block 182 and through the earn 184 and is supported in the brackets 146 and 147. The end of lead screw 150 is supported on the bracket 146 by means of ball bearing 186 and retaining cap 188 and snap ring 190 and is supported in bracket 147 by means of ball bearing 192 and snap ring 194.

A lens drive motor MOT-l is connected to the main frame 106 by bracket 196 and screws 198. Immediately beneath the motor MOT-1 and likewise attached to the rame 106 is a magnetic drive clutch and brake SC-2.

The clutch SC-2 is driven by the motor MOT-1 through belt 202 to pulley 204. FIGS. 5 and 6 show cutaway views of the clutch and brake 200. A rotor assembly 206 is fastened to the pulley 204 by means of bolts 208 and contains a magnetic field coil 210. The rotor and pulley are mounted on a bearing 212 on the shaft 150 of lead screw 150. The rotor and the pulley are freely rotatable on the bearing 212 about shaft 150. A pair of slip rings 216 encircle the rotor to provide electrical contact between the magnetic field coil and electrical brushes 218. The brushes 218 are mounted on a support rod 220 which in turn is fastened to a bracket 222 by bolt lug 224. The brushes 218 are supported on the rod 220 by clamp 226 which contains a pivot point 228 and a leaf spring 230, which pivots the brushes about the point 228 into contact with the slip rings 216. The bracket 222 is mounted on the optical frame 106 by lugs 232 and supports the entire clutch assembly SC-2 by means of lugs 234 which extend through the bracket 222 to a stationary brake member 236. The shaft 150 extends into the brake member 236 and is rotatably journaled therein in bearing 238.

A collar 240 is suitably secured to the shaft 150, as, for example, by keying, at a point along the shaft between the rotor 206 and the brake member 236. The co1- lar 240 contains a metal diaphragm 242 which'is attached to the armature 244 of the electro clutch 200. Electric current to the magnet 210 sets up a magnetic eld w-hich attracts the armature 244 pulling the armature forward against the action of diaphragm 242 until it is in contact with the rotor 206. Motion is then transmitted from the motor MOT-1 to the belt 202, the pulley 204, the rotor 206 to the armature 244. Rotation of the armature 244 produces rotation of the shaft and the lead screw 150 resulting in movement of the lens assembly 144. When power is cut off from the magnet 210, the diaphragm 242 pulls the armature back away from the rotor 206 into contact with the brake member 236, which, since it is secured to the bracket 222, provides a braking action for the movement of the shaft 150 and the lens assembly 144.

The guide shaft 148 and the lead screw 150 are constructed at an angle of approximately twenty-six minutes with a vertical plane passing through the two mirrors 98 and 102. When the leading edge of a document to be reproduced passes the scanning station, the reflected light image of the document is placed on the Xerographic drum surface so that it will ultimately appear as a developed image in a predetermined point on the copy sheet passing through the xerographic side of the machine. As the lens assembly 144 is moved to the right along the shaft 148, the light image appearing on the xerographic drum surface is reduced and, consequently, the relative position of the light image of the leading edge of the document is moved to a different position on the drum surface. The amount of variance of the leading edge of the light image on the xerographic drum surface is determined by the amount of reduction of the original document being reproduced. Thus, if the lens assembly 144 is at the extreme left-hand position of the guide shaft 148, and this is taken as the reference position upon which the leading edge of the document strikes the Xerographic drum surface, then the `movement of the lens assembly to the right on shaft 14S produces a correspondingly in` creasing departure of the light image from that original position. By angling the shaft 148 and the lead screw 150 so that the lens 144 does not travel in a plane containing the two mirrors, but rather in a plane at an angle of approximately twenty-six minutes to the plane of the two mirrors, then the leading edge of the document will be reproduced at approximately the same position on the xerographic drums surface and, consequently, in the same relative position on the final copy sheet.

The position of t'ne lens assembly is controlled by a series of switches 15LS-20LS and two override switches 28LS and 30113, shown in FIGS. 4 and 9 and described herein under Machine Operation. The switches are actuated by cam 184 on the bottom of the lens assembly and stop the lens assembly at the position desired.

founted on each side of the optical frame 106 is a mirror support casting 250 mounted at 45 to the horizontal and optically aligned with the document in the conveyor 12, the lens 104, and the xerographic drum 252 so that a light image is reflected from the document surface onto the mirror 98 through the lens 104 to the mirror 102 and the xerographic drum 252. The mirror castings 250 are supported on the frame 106 by means of bolts 251 in slotted grooves 253 and a centrally located pin through the casting and the frame. The pin is not shown in the drawings but is mounted in the side of the casting 250 so that the entire mirror assembly is rotatable about the pin member. For optical alignment purposes, the bolts 251 may be loosened and the casting 250 rotated about the pin member with a limited degree of movement being provided by the slots 253.

The casting 250 supports a housing 254 containing the mirrors 98 and 102. The housing 254 is supported in the casting 250 by means of a pin 258 on each end of the casting which is secured in the casting and loosely journaled in the housing 254. Adjustment screws 260 at one end of each casting 250 press downward on the housing 254 to prevent rotational movement of the housing about the pin 258. Adjustments may be made to the adjustment screws 258 to optically align the mirrors about an axis which runs through the pins S.

The entire optical frame 106 is guided for movement along the lead screw 110 by means of a guide assembly 262 located on the conveyor side of the apparatus. An upright guide 264 is supported from the main frame of the apparatus and extends upward to a point sufficient to guide the optical frame 106 along its entire path of travel. A support member 266 is fastened to the optical frame 106 at one end thereof and to a second member 268 containing a rolier assembly and positioned at right angles to the support member 266. The member or plate 258 contains a stationary roller 270 and a movable roller 272 which cooperate with guide 264 in the same manner as previously described for the lens guide rollers 158 and the lens guide bar 156. The roller 270 is pivotally mounted on the member 268 in contact with the guide 264. The

roller 272 is rotatably mounted on a pivot member 274 which is pivotally secured to the plate 268 by pin 276. A spring 278 is secured at one end to the plate member 268 and at its other end to the pivot member 274 urging the pivot member 274 about pin 276 and the roller 272 into rolling Contact with the guide 264.

Xerog/'ap/'n'c apparatus The xerographic or reproducing side of the apparatus receives a light image of the document being passed through the conveyor system 12 by means of the optical system 14 and converts that light image into a powder image and transfers the powder image to a sheet of support material, usually paper, and provides a permanent bond of the powder image to the paper surface. Suitable xerographic apparatus for use in this machine is disclosed in detail in Patent No. 3,078,770, issued to R. A. Hunt et al. on Feb. 26, 1963, entitled Xerographic Reproducing Apparatus. For a detailed explanation of the apparatus, reference is had to the above-entitled patent; however, for purposes of this invention, reference is had to FIGS. 2 and 7 and the following brief description of the xerographic apparatus.

The xerographic apparatus comprises a xerographie plate including a photoconductive layer or light receiving surface on a conductive backing and formed in the shape of a drum 252. The drum is journaled in the frame to rotate in the direction indicated by the arrow to cause the drum surface sequentially to pass a plurality of xerographic processing stations.

The several xerographic processing stations in the path of movement of the drum surface may be described functionally, as follows:

A charging station in which a uniform electrostatic charge is deposited on the photoconductive layer of the xerographic drum;

An exposure station at which a light or radiation pattern of copy to be reproduced is projected onto the drum surface to dissipate the drum charge in the exposed areas thereof and thereby form a latent eectrostatic image of the copy to be reproduced;

A developing station at which a Xerographic developing material, including toner particles having an electrostatic charge opposite to that of the electrostatic latent image, is cascading over the drum surface, whereby the toner particles adhere to the electrostatic latent image to form a xerographic powder image in the configuration of the copy to be reproduced;

A transfer station, at which the xerographic powder image is electrostatically transferred from the drum surface to a transfer material or support surface; and,

A drum cleaning and discharge station at which the drum surface is rst charged and then brushed to remove residual toner particles remaining thereon after image transfer, and at which the drum is exposed to a relatively bright .light source to effect substantially complete dis- Lla charge of nany residual electrostatic charge remaining thereon.

The charging station is preferably located as indicated by reference character A. In general, the charging rpparatus or corona charging device 284 includes a corona discharge array of one or more discharge electrodes that extend transversely across the drum surface and are energized from a high potential source and are substantially enclosed within a shielding member.

Next subsequent thereto in the path cf motion of the xcographic drum is an exposure station B. This exposure station receives the light image from the document being reproduced and permits that light image to be sequentially placed on the drum surface in timed relation to the movement of the original document through the document conveyor. A light image of the copy being reproduced is reflected from the mirror 102 through a slot aperture 230 in a light shield 282 onto the xerographic drum 252.

Adjacent to the exposure station is a developing station C, in which there is positioned a developer apparatus 286 including a developer housing 288 having a lower or sump portion for accumulating developer material 290. Mounted within the developer housing is a bucket type conveyor 292 to carry the developer material to the upper portion of the developer housing from where the developer material is cascaded over a hopper chtite 294 onto the drum.

As the developer material cascades over the drum. toner particles of the developer material adhere electrostatically to the previously formed electrostatic latent image areas on the drum to form a visible xerographic powder image, the remaining developer material falling off' the peripheral surface of the drum onto the bottom of the developer housing. Toner particles consumed during the developing operation to form the xerographic powder images are replenished by a toner dispenser 295, of the type disclosed in Hunt Patent No. 3,013,703, issued Dec. 19, 196i. mounted within the developer housing and driven by a motor through a suitable drive mechanism.

Any developer material not caught within the developer housing as the developer material falls from the drum is caught by a pan 298 suitably positioned beneath the developer housing. As a supply of developing material accumulates in this pan, it is manually removed by the operator and it may be returned to the reservoir in the developer housing.

Positioned next adjacent to the developing station is the image transfer station D, which includes suitable sheet feeding mechanisms adapted to feed sheets of support or transfer material, usually paper, successively to the xerographic drum in registration with the formed xerographic powder image on the xerographic drum. In the embodiment shown, the sheet feeding mechanism includes a chain conveyor 302 carrying a pair of paper grippers 304 in a circuit between sheet receiving and sheet delivery stations, means being provided to actuate the paper grippers to cause the paper grippers to take hold of the front or leading edge of a sheet of support material inserted into the machine and to hold the sheet While traveling to the delivery station and there to release the sheet for discharge from the machine.

In the embodiment shown, a sheet of transfer material is fed manually by an operator to a paper gripper 304 at sheet feed-in station 306 and is forwarded by the paper gripper into contact with the xerographic drum.

The transfer of the xerographic powder image from the drum surface to the support material is effected by means of a corona transfer device 388 that is located at or immediately after the point of contact between the support material and the rotating drum. The corona transfer device is substantially similar to the corona device 284 that is employed at charging station A, in that it includes an array of one or more corona discharge electrodes that are energized from a suitable high potential source and extend transversely across the drum surface and are substantially enclosed within a shielding member. In operation, the electrostatic field created by the corona discharge device is effective to tack the transfer material electrostatically to the drum surface, whereby the transfer material moves synchronously with the drum while in contact therewith. Simultaneously with the tacking action. the electrostatic field is effective to attract the toner particles comprising the xerographic powder image from the drum surface and cause them to adhere electrostatically to the surface of the transfer material.

As the paper gripper is advanced by the chain conveyor, it will strip the sheet of transfer material from the drum and transport it to a suitable xing device, such as heat fuser 310, whereas the xerographic powder images previously transferred to the sheet are permanently fixed thereto. There are suitable rods 312 provided to guide the trailing edge of the sheet of support material in a path adjacent to the heat fuser. The heat fuser 31() contains suitable electric heating elements 1?.-1, R-Z, and R-3 connected to a suitable source of power to provide the necessary heat to fuse the powder image to the support material surface.

After fusing, the finished copy is discharged from the apparatus at discharge point 3l4 from which it falls to a hopper 316 at the front of the apparatus. To accomplish this, there is provided a pair of delivery rollers 318 and 320 which receive the sheet from the paper gripper and deliver it to a paper chute 322.

The next and final station in the device is a drum cleaning station E, having positioned therein a corona precleaning device 324 similar to the corona charging device 284. An electrostatic charge is imposed on the drum and powder adherent thereto to aid in effecting removal of the powder. A rotatable brush 326 rotates in contact with the drum surface to effect the removal of the residual powder from the drum, and a light source LMP4 floods the drum surface with light to cause dissipation of any residual electric charge remaining on the xerographic drum.

For collecting powder particles removed from the brush, there is provided a dust hood 328 that is formed to encompass approximately two-thirds of the brush area. For removing dust particles from the brush and the dust hood, an exhaust duct 330 is arranged to cover a slot that extends transversely across the dust hood 328 and is connected to a filter bag 332 in a lter box 334. Motor driven fan units 336 connected to the filter box produce a flow of air through the filter box drawing air through the area surrounding the Xerographic drum and the dust hood entraining powder particles removed from the drum by the brush. Powder particles are separated from the rair as it flows through the filter bag so that only clean air reaches the motor fan unit.

The operation of the xerographic apparatus is discussed below in conjunction with the entire machine operation.

Drive system FIGS. 2, 8 and 11 show the drive system for the conveyor, the optics, and the xerographic equipment. The motor MOT-7 is the main drive motor of the apparatus and supplies power to drive the xerographic drum 252, the xerographic chain conveyor 302, the document conveyor drive roll 24, and the optical assembly 14. The motor MOT-7 is mounted at the bottom of the machine on a support bracket mounted on the main frame. The output shaft of the motor drives a power shaft 340 through a gear box 342. A large pulley 344 is mounted on the shaft 340 and drives a belt or chain 346. The belt 346 conveys power to the mirror drive transmission 142 by means of pulley 348 mounted on the input shaft 350I of the mirror drive transmission. The mirror drive transmission 142 is shown in detail in FIGS. 14, 15 and 16.

As seen in FIG. 14, the power input shaft 350, containing the sprocket 348, extends through a side wall 352 and is journaled in the side wall by ball bearings 354. The shaft extends through the mirror drive transmission to the opposite wall 356 wherein it is journaied in ball bearing 358 and extends through the wall 356. The space between the walls 352 and 356 is enclosed a top plate 360 and a bottom plate 362. The side wall 356 contains an extended portion 364 about the periphery forming, in conjunction with the side wall 356 and a side cover plate 366, an enclosed gear box 368. The side cover 366 is removably mounted on the extended periphery 364 of the side wall 356 by means of bolts or lugs 370, thus providing access to the interior of the gear box 368. The top cover 360 and the bottom cover 362 are removably secured to the side walls 356 and 352 by means of screws 372 providing access to the interior of the mirror drive transmission. A gear 374 is mounted on the end of the shaft 350 that extends through the wall 356 into the gear box 368. The gear 374 is rotatably secured to the shaft 350 by means of key 376 and is held on the shaft 350 by means of nut 378 on a threaded portion of the end of shaft 350.

A second shaft 380 is journaled for rotation in ball bearings 382 and 384 in side walls 352 and 356, respectively, beneath the input shaft 350. The shaft 380 is freely rotatable and also extends through the wall 356 into the gear box 368. A second gear 386 of the same size as gear 374 is mounted, in the gear box 368. on the end of shaft 330 by means of key 338 and nut 390 in the same manner as gear 374. The gears 374 and 386 mesh to impart motion from the input shaft 350 through the gear 374 to the gear 386 and to the shaft 380. This particular arrangement provides rotational movement of two shafts in opposite directions, that is, if the ends of the shafts are viewed from the left-hand side of FIG. 14, looking into the gears 374 and 386, the upper or input shaft 350 rotates in one direction, say counterclockwise, then the second shaft 380 will have a rotational movement in a clockwise direction. Therefore, the mirror and optics assembly 14 may be driven in an upward or a downward direction by taking the driving motion either from the shaft 350 or the shaft 380.

Mounted in the mirror drive transmission 142 between the walls 352 and 356 and on the shafts 350 and 380 are a pair of magnetic clutches generally indicated as SC-3 and SC-4, respectively. The two magnetic clutches are identical in construction so that, for purposes of simplicitv. only the clutch SC-4, shown in section view, will be described herein. The clutch construction consists basically of an armature 396 mounted on the shaft 350 for rotational movement therewith by means of key 398 and key way 399. Lateral movement along the shaft is restricted by means of a pair of set screws 402, one of which is shown. A clutch plate member 404 is mounted on the armature 396 by means of a resilient metallic diaphragm 406. A rotor 403. containing an electromagnet 410, is mounted on a sleeve bearing 412 for independent rotation on the shaft 350.

A pair of support arms 314 are secured to the side walls 356 by lugs 316 and contain mounted thereon a pair of electrical brushes 318 in electrical contact with conductive rings 420. The brushes 318 supply electrical current to the electromagnet 410 through the rings 420 during rotation of the rotor 408. When current is supplied to the electromagnet 410, a magnetic field is set up which attracts the clutch plate 406 and pulls it against the action of diaphragm 404 up against the rotor 408, providing the clutch action necessary to drive the rotor 408 from either the shaft 350 or 380 through the armature 396, the clutch plate 404 to the rotor 403. When the electrical conta-:t is broken, the field and the electromagnet are cut off and the diaphragm 404 pulls the clutch plate 406 away from the rotor 40S, removing any driving action from the rotor.

Each of the magnetic clutches SC-4 and SC-3 have a sprocket 422 and 424, respectively, secured to the rotor 11 408 by means of three bolts 425, only one of which is shown.

A chain 428 engages both sprockets 422 and 424 and a third sprocket 430 secured to a shaft 432 by a key 434. Motion imparted to either of the sprockets 422 or 424 by the magnetic clutches SC-3 or SC-4 is relayed to the sprocket 430 in the shaft 432 by means of the chain 42.8. The shaft 432 enters a gear box 436 wherein the rotary motion set up in shaft 432 is used to produce a corresponding rotary motion in shaft 138 by means of a standard set of bevel gears, as is well known in the art. As previously described, the shaft 138 is connected to a linkage member 134 by means of a universal joint 136 so that the rotary motion of the shaft 138 is imparted to the lead screw 110 of the optic system 14.

Operation of the magnetic clutches SC-3 and SC2-4 is controlled by a series of eight switches, 21LS through 251.8 and two override switches 271.5 and 291.5. The override switches and two of the positioning switches switches 211.5, 231.5, 251.5, and 261.8 are shown in FIG.

11. The other four positioning switches cannot be seen in FIG. 11 since they are paraliel with the switches shown. The switches are adjustably mounted on a bracket 440 and vertically positioned to control the stopping point of the mirror assembly for the proper reduction of the document being reproduced. The switches are horizontally positioned in the bracket 440 so that their actuating arms are contacted by a cam 444 extending outward from the back of the optical frame or casting 105. As the whole optical assembly 14 is moved upward or downward, the cam 444 successively contacts the actuating arms of the switches and, depending upon the particular document reduction desired by the operator, the magnetic clutch and the mirror drive transmission 142 will be deenergized, as described below with respect to the overall operation of the apparatus.

The shaft 340 from gear box 342 of motor MOT-7 contains, in addition to sprocket 344, a pulley 446, which drives belt 448. Belt 448 transmits power from the motor MOT-7 to pulley 450 on shaft 452. The shaft 452 is rotatably supported by a pair of arms 454 mounted on inner support frame 456. The inner support frame 456 also supports a document drive transmission 458. The shaft 452 is rotated by pulley 450 and belt 448 and contans a second pulley 460 and a sprocket 462 mounted thereon. The pulley 4-50 transmits power from the shaft 452 to a Xerographic drum drive belt 454. Belt 464 transmits power to the xerographic drum 252 by means of pulley 466 mounted on shaft 458, which in turn is coupled with the xerographic drum 252. Shaft 463 is rotatably journaled in the Xerographic frame plates 470 and 472 and an interior frame plate 474. The belt 464 is tensioned by two idler rollers 476 and extends around a pulley 478 on the power input shaft 480 of the document drive transmission 458, thus supplying power to the document drive transmission. It is obvious from the foregoing that the Xerographic drum is driven at a constant speed during the time t .at the motor MOT-7 is in operation, and the input to the document drive transmission 458 is also driven at a speed proportional to the speed of the xerographic drum.

The sprocket 452l on shaft 452 drives the paper conveyor system of the xerograpbic apparatus through chain 482 to sprocket 484 and to delivery roller 320. The chain 482 is driven during operation of the motor MOT-7 in the same manner as the xerographic drum drive; however, the paper conveyor of the Xerographic apparatus is operated intermittently in conjunction with the operation of the document conveyor 12. The intermittent operation of the paper conveyor is accomplished through a clutch 436, shown in detail in FIG. 13.

A sheet material conveyor suitable for use herein is described in detail in Patent No. 3,078,770, issued to R. A. Hunt et al. on Feb. 26, 1963. Therefore, the following general description of the conveyor and clutch mechanism is suicient for this disclosure. As seen ia FlG. 7, the

roller chains 302 carrying the paper grippers 304 are driven sprockets 488 secured to drive shaft 490, which is rotatably journaled in frame plates 470, 472 and 474. Drive shaft 490 is maintained axially in position at one end by a collar 492 and thrust washer 494, and at its other end latter being inserted in a suitable groove fromed in the drive Shaft. Drive shaft 490 is driven by sprocket 484 through a conventional magnetic clutch SC-l. The magnetic clutch includes two clutch plates 502 and 504.

Clutch plate 502 is secured to the drive shaft 490 for rotation therewith by key 506 and screws 508 threaded in the hub of clutch plate 502. The clutch plate 504 is journaled by suitable bearings on the drive shaft and carries a clutch adapter 510 supporting sprockets 484 driven by chain 432, as previously described. Th. clutch plate 504 is free to rotate about the axis of the drive shaft while the clutch plate 502 remains stationary due to friction of the elements attached thereto.

The magnetic clutch is connected to a suitable source of power, as described hereinafter, through brushes 512 bearing on suitable collector rings on clutch plate 504, the brushes being secured to, and insulated from, the frame plate 474 by bracket 514. When power is supplied to an electromagnet within clutch plate 504, through brushes 512, the magnetic field set up closes the rotating clutch face of clutch plate 504 against the clutch plate 582 transmitting power from the sprocket 484 through the clutch SC-l to the shaft 490 transmitting the necessary drive to the conveyor chains 302 and gripper 'oars 304.

As previously indicated, power is supplied from the motor MGT-7 through belt 448, the xerographic drum drive belt 464 to the input shaft 480 of the document drive transmission 458. The output shaft 516 of the document drive transmission is seen in FIG. 2, and has pulley 518 mounted thereon. A belt 520 transmits power from the document drive transmission 458 to the document drive roll 24 which moves the belt system of the conveyor 12, as previously described, to carry a document through the exposure station. The movement of a document through the document conveyor 12 must be proportional in speed to the movement of the Xerographic drum 252. That is, assuming a one-for-one size reproduction of a document, the conveyor would have 'to move the doctimcnt at the same linear speed as the surface of the xerographic drum 252. Assuming that there were to be a fifty percent reduction in the size of the copy from the original document, the document conveyor would necessarily move at twice the speed of the linear movement of the surface of the xerographic drum. Therefore, the document drive transmission must accurately synchronize the movement of the Xerographic drum and the conveyor system and must be capable of selectively producing variations in the ratio of the document speed to the drum speed.

A document drive transmission of the type suitable for use herein is disclosed in copending application, Ser. No. 299,416, led Aug. 1, 1963, in the names of E. D. Hewes. R. R. Tilly, and J. O. Wilson, now Patent No. 3,220,275.

Machine operation A clearer understanding of the operation of the rnachine can best be obtained by reference to the schematic wiring diagram, FlGS. 17 and 18, the control panel in FIG. l, and the following description.

Before the apparatus may be actuated, the doors of the cabinet must be closed to actuate the interlock switches ILS, 21.8, BLS and 41.8, mounted on the cabinet frame. These interlock switches are used so that the machine may be operated only when the doors of the cabinet are closed. A further interlock switch 31LS is positioned on the conveyor lamp housing to be actuated by thrust washer 496 and retaining ring 498, the

by closing the lamp housing. These provisions are made not only from the standpoint of safety, but also to insure proper circulation of air through the interior of the machine to dissipate heat generated by the apparatus and to assure proper illuminationl of any document passing through the machine.

The paper grip-per 304 must be in a position to receive a sheet of support material before a reproduction is made. For that purpose, a switch actuator 305 on the paper conveyor contacts an end-of-cycle limit switch 7LS-A to stop the paper conveyor with a paper gripper at the receiving station ready to receive a sheet of support material.

The entire machine is originally energized by momentarily closing a main power switch SW-l connecting the assembly to a suitable source of power such as a commercial 220 volt alternating current outlet. Switch SW-l is a manually operable, mechanically interlocked switch having contacts SW-1A, SW-lB and SW-lC. Switch SW-lA is momentarily closed by depressing the button on the control panel marked ON. At the same time, the contacts SW-IB are momentarily opened.

Upon closure of switch SW-lA, control relay ICR is energized to close its contacts ICR-1, ICR-2, ICR-3, 1CR-4 and ICR-5. With the closure of contact ICR-1, the switch SW-lA may be released, the circuit then being maintained through contacts ICR-1, the normally closed contact 4TR-A of thermal timer 4TR, and normally closed switch SW-2 to supply power to the control relay lCR to keep its contacts closed. Switch SW-2 is controlled by the button on the control panel and serves to completely de-energize or shut down the apparatus. At the same time, transformers T-Z and T-3 are energized along with the power supply PS-l which supplies high voltage power to the corona charging device 284, the corona transfer device 308 and the corona precleaning device 324. Fluorescent lamp LMP-4 is also energized through a conventional starter S-1 and ballast L-1 circuit.

Switch SW-S, which is a mechanically interlocked three-position, push-button switch is used to control the voltage applied to the resistance elements of the heat fuser 310. Switch SW-8 is shown on the control panel of the apparatus in a suitable location to be accessible by the operator. As shown, the different contacts of switch SW-S are connected to different secondary taps of the multiple tap transformers T-2 and T-3 to supply preselected voltages to the resistance elements R-1, R-2 and R3 of the heat fuser 310.

As transformers T-2 and T-3 are energized, power is supplied directly to the resistance element R-1 which is the heating element of the fuser normally used, and through the normally closed contact STR-A to the resistance element R-2 and R-3. Resistance elements R-2 and R-3 are used as an auxiliary heating element to aid in bringing the heat fuser up to its normal operating temperature rapidly. Thermal timer STR, which is also energized upon the closure of switch SW-l and contact ICR-2, is a G-second timer, that is, 300 seconds after it is energized while at ambient room temperature it will heat up sufficiently to open its contact 3TR-A thereby de-energizing resistance element R-2.

If the machine is operated for a sul'licient period of time to permit the heat fuser to be brought up to its normal operating temperature and then the machine is shut down, there will be considerable time delay before the heat fuser will cool sufficiently to reach ambient room temperature. Now, if the machine is againenergized and the resistance element R-2 is again energized for a threeminute interval, there would be sufiicient heat capacity left in the fuser so that with the additional heat supplied by resistance element R-2 the fuser would become overheated to the extent that a support material, such as paper, passing therebeneath would be scorched. To prevent this, a thermal timer 3TR is chosen with a characteristic curve such that it too will have an extended period of time in which to cool down sufliciently to close its contacts STR-A. With a timer of this type, it is then possible to re-energize the machine after a brief shut down interval without overheating the fuser because a 30G-second cycle will no longer be necessary to heat up the timer 3TR to open its contacts STR-A. r'

The third resistance element R-3 can be connected by an operator, if required, in order to fuse powder images on card stock, master stock, or heavy transfer material, for which a higher heat output is necessary. For this purpose, there is provided a switch SW-9, positioned on the apparatus control panel for access by the operator.

Simultaneously with the closure of switch SW-l the following motors are energized: The main drive motor MOT-7 for driving the xerographic drum, the document conveyor, the support material conveyor and the mirror assembly; a brush cleaner motor MOT-6 suitably connected for rotating the cleaning brush 326; the motor MOT-8 for operating the developer conveyor 292 and the toner dispenser 296; and the motor MOT-3 for blower 336; and motors MOT-4 and MOT-5 for circulating air within the machine and for removing exhaust heat from the fuser unit and also motors MOT-9 and MOT-10 which operate blowers to remove heat from the document lamps LMP-1 and LMP-2.

The main drive motor MOT-7 and the developer drive motor MOT-8 may be controlled by switch SW-7 for the purpose of cleaning the xerographic drum. With the switch SW-7 in the normal operating or OFF position, the motors MOT-7 and MOT-8 are under the control of main power switch SW-1A, and contacts ICR-2 whereby power is supplied immediately to the main drive motor MOT-7 upon the closure of the switch SW-1A and to motor MOT-8 by the closure of normally open contacts 7CR-2. When the machine is shut down, the switch SW-7 may be turned to the ON position whereby the motors MOT-7 and MOT-8 are operated directly from line current rather than through switch SW-IA. This procedure permits the drum to be rotated for solvent cleaning and the developer to be operated during changing of the de veloper charge. The actuation of switch SW-IA and the closure of contact ICR-4 also produces immediate illumination of uorescent lamps LMP-1 and LMP-2, located over the platen in the document conveyor, through the conventional induction circuit L-2.

As contacts ICR-2 are closed, a 20-second timer 2TR is energized as is the 41/2 minutes shutdown timer 4-TR. Timer 4TR is energized through normally closed contacts 2CR-2 and 7CR-1 and, if left energized for 41/2 minutes, would open its contacts 4TR-A to de-energize the machine circuit. The thermal timer 2TR provides a 20-second time delay after the initial operation of the machine; that is, after actuation of switch SW-IA, the normally open contacts 2TR-A in the paper gripper bar circuit are not closed for 20 seconds so that the gripper bar will not accept a sheet of support material until the fuser has been heated sufficiently to fuse the powder image on the support material.

Assuming that the gripper bar is in the home position so that switch 7LS is actuated by switch actuator 305 on the conveyor chain 302, then the contacts 7LS-A have been closed and when the timer ZTR actuates contacts 2TR-A, after a 20-second delay, the print load lamp LMP-6, also shown on the control panel, is lit through the circuit consisting of contacts ICR-2, 7LS-A, ZTR-A and the normally closed contacts SLS-B. The machine is thus indicated to be ready to make a xerographic reproduction.

The operator may now insert a sheet of support material into the paper gripper 304. The leading edge of the support material will trip the actuator of the limit switch SLS to thereby open contacts SLS-B cutting off the circuit to the LMP-6 and closing the contact SLS-A energizing a two-second thermal timer 1TR which, after the twosecond time delay, actuates its contact 1TR energizing 

1. AN OPTICAL SYSTEM FOR USE IN A DOCUMENT REPRODUCING APPARATUS OF THE TYPE WHEREIN ENLARGED OR REDUCED COPIES ARE MADE OF AN ORIGINAL DOCUMENT INCLUDING: A SUPPOR COLUMN; A FRAME MOVABLE ALONGE THE LENGTH OF THE SUPPORT COLUMN; MEANS TO MOVE THE FRAME ALONG THE LENGTH OF THE SUPPORT COLUMN TO VARY THE LENGTH OF A LIGHT PATH WITHIN THE DOCUMENT REPRODUCING APPARATUS; A LENS ASSEMBLY MOVABLY MOUNTED ON THE FRAME; AN OBJECTIVE MIRROR SUPPORTED ON THE FRAME A SOURCE OUTTO REFLECT A LIGHT IMAGE RECEIVED FROM A SOURCE OUTSIDE OF THE OPTICAL SYSTEM TO THE LENS ASSEMBLY; AN IMAGE MIRROR SUPPORTED ON THE FRAME IN A POSITION TO REFLECT A LIGHT IMAGE RECEIVED FROM THE LENS ASSEMBLY TO A POINT OUTSIDE THE OPTICAL SYSTEM; MEANS TO MOVE THE LENS ASSEMBLY TO PRESELECTED POSITIONS BETWEEN THE OBJECT MIRROR AND THE IMAGE MIRROR; CONTROL MEANS TO COORDINATE THE POSITION OF THE OPTICAL FRAME ALONG THE COLUMN AND THE POSITION OF THE LENS ASSEMBLY INCLUDING: A FIRST SERIES OF SWITCHES WITH ACTUATING MECHANISMS POSITIONED IN INTERFERENCE RELATIONSHIP WITH THE MOVEMENT OF THE FRAME ALONG THE LENGTH OF THE SUPPORT COLUMN, A SECOND SERIES OF SWITCHES WITH ACTUATING MECHANISMS POSITIONED IN INTERFERENCE RELATIONSHIP WITH THE MOVEMENT OF THE LENS ASSEMBLY, AND 